1. Field of the Invention
The present invention relates to an individually adaptable leak fuel connection for a component that has a leak fuel line. In particular, the present invention relates to a leak fuel connection for a holder of an injector in a common rail system.
2. Description of the Prior Art
In FIGS. 10 and 11, a known leak fuel connection is shown. In a holder 18 for a common rail system, in which a piezoelectric element and a hydraulic booster are disposed (neither of them shown), the leak fuel connection is embodied such that a leak fuel line 2 communicates via a connecting conduit 3 directly with the connection end piece 4. As shown in FIG. 11, still other bores, namely a high-pressure bore 19 and a bore 20 for an electrical connection of the piezoelectric actuator are provided in the holder 18. Since these many bores are disposed in the holder 18 eccentrically to a center axis 0xe2x80x940 of the holder 18, the connecting conduit 3 embodied as a transverse bore cannot extend in an arbitrary direction in the holder 18, because otherwise a communication with one of the bores 19, 20 could be made. Moreover, between the various bores, for the sake of high-pressure strength, minimum spacings must be adhered to so as to withstand the high pressures, in particular in a common rail system. Because of these circumstances, the connecting conduit 3 can accordingly not be disposed in an arbitrary direction in the holder 18. Because of this xe2x80x9crigidxe2x80x9d leak fuel connection in the prior art, it is not possible to adapt the leak fuel connection individually to different vehicles. On the contrary, the leak fuel connection must be disposed in such a way that no communication with the bores provided in the holder 18 is created, or a minimum wall thickness of the various bores must be preserved. This greatly limits the disposition of the leak fuel connection.
The leak fuel connection of the prior art is thus adaptable only in a limited way to the most various engine compartment geometries of different vehicles or manufacturers. For this reason, a great number of different holders for piezoelectrically controlled injection systems already exist in order to meet the demands of a particular customer. The result is increased costs, since a great number of different parts have to be kept on hand, or different production processes must be performed.
The leak fuel connection of the invention has the advantage over the prior art that it can be disposed entirely flexibly on the component in which a leak fuel line is provided. By the provision of an at least intermittently annularly embodied conduit on the outer circumference of the component that has the leak fuel line, it can be assured that the leak fuel connection can be disposed at any arbitrary angle on the circumference of the component. To that end, the at least intermittently annularly embodied conduit communicates with the leak fuel line via a connecting conduit. The connecting conduit between the leak fuel line and the annular conduit can be disposed at an arbitrary point in the component. Via a connection element, a connection end piece of the leak fuel connection is then disposed on the annular conduit. This makes it possible, for different engines or different engine manufacturers, to adapt the leak fuel connection individually in terms of its length, angle and height. Thus according to the invention a flexible leak fuel connection is furnished that can be adapted to the most various geometries. Thus even when the engine compartment geometry is tight and installation conditions are also tight, the leak fuel connection can be disposed in an arbitrary position. Moreover, this leads to an additional unification of the component that has the leak fuel line, since the connecting conduit between the leak fuel line and the annular conduit can always be disposed at the same point. In particular, the flexible leak fuel connection of the invention is used in an injector unit in a common rail system for the leak fuel from a hydraulic booster for hydraulic boosting of a stroke of a piezoelectric element.
In a preferred feature of the present invention, the connection element that connects the annular conduit to the connection end piece is embodied as a flexible hose. This makes it possible for the hose to be rotated in arbitrary direction and at any arbitrary angle, so that the connection end piece of the leak fuel connection is disposed at a desired position. Especially preferably, the flexible hose is made from plastic.
In a further preferred feature of the present invention, the annular conduit is embodied as a completely encompassing annular groove, which extends along the outer circumference of the component. As a result, the connection element can be disposed at any desired point along the completely encompassing annular groove. The annular groove can have an arbitrary cross section. By means of the connecting conduit, the annular groove communicates with the leak fuel line. The component can thus be standardized with regard to the production steps necessary for the leak fuel connection.
To make a stop function and bracing of the connection end piece on the connection element possible, a support ring is preferably provided on the connection element. The support ring is disposed on the outer circumference of the connection element and is embodied for instance as a perforated disk, which is connected to the connection element by means of a press fit.
To enable protection of the annular conduit in subsequent machining steps, an inlay element is preferably provided, which is disposed around the annular conduit.
Preferably, a shoulder or an annular groove is provided for retaining the inlay element.
So that the inlay element can provide the annular conduit with an adequate sealing function, its sealing edge profile is embodied as a circular segment profile, sawtooth profile, pyramid profile, or a single or multiple hollow profile.
In a preferred feature of the present invention, the inlay element is embodied in two parts. One part is preferably embodied as a fabric inlay, and another part is embodied as a plastic inlay. The plastic inlay offers protection to the fabric inlay against external factors.
To enable a concluding fixation of the connection element and of the connection end piece secured to it, a plastic extruded sheath is provided in the region of the leak fuel connection. As a result, the leak fuel connection is retained in its desired final position, and protection against external factors is also afforded.
In order to use the smallest possible number of parts, the connection element and the connection end piece are preferably embodied integrally. Preferably, this integral component is made from plastic.
In another preferred feature of the present invention, the annular conduit can also be embodied such that it comprises a plurality of annular segments that are formed at different heights along the outer circumference and that communicate with one another via vertical connecting conduits.